It's a stretch, but the Benedictans are also known as the Olivetans.
I'm so tired of this Malachy nonsense. The Olivetan congregation was one among many reform Benedictine groups of the later Middle Ages. And to go from Malachy's "Olive" to Olivetan is just word association and to go from the Olivetan congregation to "Benedectine" in general is nonsense and then to associate Benedict XVI with "Benedictine monks"--that's four absurd leaps by mere word association in a row.
Astrology, clarivoyants etc. all depend on leaps like this--if you try hard enough, you can connect just about anything with anything. The Malachy stuff is utter nonsense. But those who have become adepts of it are so crazed by it that they can't even hear these sorts of objections.